Viscometer



VISCOMETER Filed Sept. 4, 1936 25 lNVENTO R g @6 Y -Zme/ /i Payne 4 I 24mm ATTORNEY V atentecl May 10, 1938 Elmerii. Payne, W ver, illiL, amignor to Standard Oil Company,

ration of India cam. Hit, a corpo- Application Septcmr d, 1936, Serial No. 99,360

This invention relates to viscometers and in particular to improved. means for withdrawing excess oil in the operation of viscometers such as Saybolt universal and Saybolt furol instruments.

the well-known Saybolt instrument used in de-.

termining the viscosities of petroleum products and lubricants. This instrument and its use are described in the A. S. T. M. Standards published by the American Society for Testing Materials. The A. S. T. M. designation is D8833. My invention relates to an improvement in instruments oi this type.

One of the objects of my invention is to make possible the easier and more accurate withdrawal of liquid from the overflow cup. Other objects of my invention are to provide excess oil withdrawal means which can be conveniently operated, which can be installed on existing instruments without difiiculty, which will operate in every instance in precisely the same way so that the human equation is eliminated, which will' avoid much of the mess and inconvenience incident to present operations, and which will have further advantages which will become apparent as the description of my invention proceeds.

My invention will now be described more particularly with reference to the accompanying drawing in which:

Figure l is a top plan view of a Saybolt viscometer, of the type sold by the American Instrument Company, provided with four viscometer tubes;

Figure 2 is a sectional elevation taken along the line 2-4 of Figure 1, showing the top of one of the viscometer tubes together with the corresponding overflow cup and withdrawal device, a

' portion of the tube and overflow cup being broken away; i Figure 2A is a fragmentary portion of my withdrawal device showing a. modified withdrawal tube tip;

Figure 3 is a vertical elevation showing the valve and pivot portion of my withdrawal device;

Figure 4 is a transverse sectional elevation through the pivot and valve portion of my device;

Figure 5 is a sectional elevation of a modified form of my withdrawal device showing the top of a viscometer tube together with the overflow cup and the modified withdrawal device, a portion of the tube and overflow cup being broken away; and

Figure 6 is an enlarged vertical section of a withdrawal tube tip of my device showing a modified valve means.

Referring more particularly to Figure 1, it will be seen that cover 0 l at the top of the viscometer bath (not shown) is aflixed to the body of the bath by wing nuts H2. The viscometer shown has four viscometer tubes it, the tops of which are surrounded by overflow cups M projecting through cover H. An opening it is provided for a bath thermometer and an opening It is provided for stirring equipment (not shown). All of the foregoing parts are conventional.

' Figure 2 shows a portion of one of the viscometer tubes it in elevation and shows the structure of overflow cup it which projects above cover H. In the use of this type of viscometer, the practice is to fill tube It, with the liquid whose viscosity is to be determined, to a level well above rim ll which forms the top of tube l3 as well as a rim of cup 14. The thermometer is then inserted in the liquid in tube l3 and the temperature is adjusted to the proper value. The thermometer is then withdrawn and (according to the prior art method) excess oil is removed from overflow cup H by manually inserting a pipette or suction tube into overflow cup H to withdraw suiflcient liquid to bring the liquid level in overflow cup ll below the level of the liquid in tube IS. The test is then conducted by opening the bot- .tom of tube 13 (not shown) and determining the time required for a specified volume to drain from tube ll. The equipment for accomplishing this is conventional and the procedure is extremely well-known.

It is most important that the greatest care be used in withdrawing the excess liquid from the overflow cup since if the pipette or other withdrawal device is allowed to touch overflow rim II, the overflow rim may be damaged and the liquid meniscus at the top of tube It! will inevitably be altered. I have found that this creates very important errors in the readings obtained from the viscometer. Furthermore, appa= ratus of this type is usually operated by rather low grade operators and it is practically inevitable that the pipette or withdrawal device will be used carelessly, for instance by running it around the overflow cup in such way as to damage rim l1 and alter the oil surface at the top of tube l3.

My invention overcomes these difficulties and iii provides simple and convenient apparatus for withdrawing excess oil from the overflow cup. It also avoids much of the mess and inconvenience occasioned by the use of a pipette.

The withdrawal device of my invention comprises a main suction tube |8 closed at one end and connected at the other end to a source of suction not shown. When used in connection with instruments having a plurality of viscometer tubes, this main suction tube acts as a manifold to which individual withdrawal devices for each viscometer tube are attached. However, it should be understood that precisely similar equipment can be used to advantage in connection with a viscometer having a single tube. A take-oil suction tube l9 rises from main suction tube l8 in the vicinity of each viscometer tube, as best shown in Figures 2 and 3. This take-oil suction tube connects with a pivot and valve device consisting of a stationary member 20 and a rotatable member 2|. These two members are held together by a bolt 22 which passes through them and by a spring 23 which cooperates with bolt 22, as shown in Figure 3, to exert pressure on members 20 and 2| to hold them tightly together. The inner faces of these two members are, of course,1carefully machined so that they will flt tightly without leakage.

As shown in Figures 3 and 4, members 28 and 2| each contain a channel having a right angle bend. These channels are made by drilling two holes, one parallel to the faces of members 28 and 2| and one at right angles to those faces. The two holes meet and connect to form the channel. Hole 24 in stationary member 28 communicates with the interior of take-off tube l8 which is integrally attached to member 28. Hole 25 in member 28 and hole 26 in member 2| are so positioned with respect to each other that they will be in alignment when movable member 2| is in one definite position. Figure 4 shows these two channels in alignment to form a continuous suction passage.

Attached to movable member 2| in alignment with hole 21 therein is a curved withdrawal tube 28. When this withdrawal tube is pulled downward to the position shown in full lines in Figure 2, it extends into overflow cup I4 without touching rim Withdrawal tube 28 contains a notch 29 so that it can exert suction even though it is against the bottom of overflow cup l4. This same result can, of course, be accomplished as shown in Figure 2A by slanting the end 28a of withdrawal tube 28 so that it will not completely contact the floor of overflow cup H. When withdrawal tube 28-is in the operative position, i. e. when it projects into overflow cup II, the channels in valve members 28 and 2| are in alignment so that suction is exerted through main suction line I8, take-oi! suction line l9, the channels in valve and pivot members 28 and 2| and withdrawal tube 28. Thusyexcess oil is removed from overflow cup I! and this withdrawal 'is accomplished without any possibility of the withdrawal device touching the walls of overflow cup ll (and particularly rim since the device is permanently positioned in such manner that this is impossible. The device will act in precisely the same way when repeatedly used and thus tests can be accurately reproduced and accurately compared to an extent not possible with the ordinary withdrawal procedure.

When withdrawal tube 28 is lifted to the position shown in dotted lines in Figure 2, the channels in members 28 and 2| are out of alignment and the suction effect automatically ceases. In Figure 1 the second withdrawal device is shown in lowered or operative position and the other three are shown in raised or inoperative position.

The whole withdrawal equipment can very readily be attached to existing viscometers since it is only necessary to attach withdrawal suction tube ill to the top of the viscometer by brackets 38 or otherwise.

It is not necessary to use combination valve and pivot devices. Thus as shown in Figure 5 the withdrawal tubes can be connected to the main suction tube by simple pivot or swing joints 30' and the suction can be controlled by springtype valves located near the free ends of the withdrawal tubes as shown in Figures 5 and 6. These valves can be independently opened manually against the spring pressure of valve 3| of Figure 5 or can be made to operate by the pressure of the tip of the withdrawal tube against the floor of the overflow cup as the valve assembly 32 shown in Figure 6 in which a disc valve 33 provided with a projection 34. is forced against a valve seat 35 by a spring coil 36. The spring coil 36 is positioned about the valve stem 31 which reciprocates through the valve stem guide member 38. When the withdrawal tube 28 is lifted out of contact with the bottom of the overflow cup H the spring 38 forces the disc valve 33 against the valve seat 35 thereby shutting off the suction. When the withdrawal tube 28 is brought in contact with the bottom of the overflow cup H the projection 34 of the disc valve 33 forces the valve 33 away from the valve seat 35 thereby opening the suction line and permitting the withdrawal of the oil from the overflow cup l4 through the withdrawal tube 28 and suction line l8.

While I have described my invention in connection with certain speciflc embodiments thereof, it is to be understood that these are by way of illustration rather than by way of limitation and I do not mean to be limited thereby but only to the scope of the appended claims which should be construed as broadly as the prior art will permit.

I claim:

1. In combination, a viscometer tube, an overflow cup surrounding the top of said tube, a suction line, a withdrawal tube cooperating with said suction line and adapted to cooperate with said overflow cup to withdraw excess liquid therefrom, said excess liquid being withdrawn through said withdrawal tube and said suction line, and valve means associated with said withdrawal tube.

2. In combination, a viscometer tube, an overflow cup surrounding the top of said tube, the top of said tube projecting slightly into said overflow cup, a suction line in flxed position, a.

withdrawal tube, said withdrawal tube being movable between an operative position in which one end thereof projects into said overflow cup without touching the top of said viscometer tube and an inoperative position in which said end is remote from said cup, and means connecting said suction line and said withdrawal tube to permit relative motion of said withdrawal tube with respect to said suction line and to control the motion of said withdrawal tube so that it can have one and only one operative position.

3. In combination, a viscometer-tube, an overflow cup surrounding the top of said tube, a suction line, a pivot device attached to said suction line, said pivot device having a passage thereiii a1 raves through communicating with said suction line, and a withdrawal tube attached at one end to said pivot device and communicating with said passage, the end of said withdrawal tube opposite the end attached to said pivot device being adapted to project into said overflow cup at a fixed position therein.

4. In combination, a viscometer tube, an overflow cup surrounding the top of said tube, the top rim of said tube projecting slightly into said overflow cup, a suction line in fixed position, a withdrawal tube, said withdrawal tube being movable between an operative position in which one endlthereoi projects into said overflow cup without touching the top rim of said viscometer tube and an inoperative position in which said end is remote from said overflow cup, means connecting said suction line and said withdrawal tube adapted to permit relative motion of said withdrawal tube with respect to said suction line and to control the motion of said withdrawal tube so that it'can have one and only one operative position, said means providing a suction passage from said suction line to said withdrawal tube when said withdrawal tube is in said operative position and serving to interrupt said passage when said withdrawal tube is in inoperative position.

5. In combination, a viscometer tube, an overflow cup surrounding the top of said tube, the top rim of said tube projecting slightly into said overflow cup, a suction line, a combination valve and pivot device attached to said suction line, said device having a passage therethrough, one end of said passage communicating with said suction line, and a withdrawal tube attached at one end to said combination valve and pivot device and communicating with the other end of said =1 go. said withdrawal tube being movable by virtue of said combination valve and pivot device between an operative position in which the free end of said withdrawal tube projects into said overflow cup without touching the top rim of said viscometer tube and an inoperative position in which said free end is remote from said overflow cup, said passage being uninterrupted when said withdrawal tube is in operative position and interrupted when said withdrawal tube is in inoperative position.

6. In combination, a viscometer tube, an overflow cup surrounding the top of said tube, the top rim of said tube projecting slightly into said overflow cup, a suction line, a combination valve and pivot device comprising a fixed member and a movable member, means for holding said two members in juxtaposition at a surface of relative motion between said two members, said fixed member being attached to said suction line, a withdrawal tube attached to said movable member, said withdrawal tube being movable by virtue of said combination valve and pivot device between an operative position in which the free end of said withdrawal tube projects into said overflow cup without touching the top rim of said viscometer tube and an inoperative position in which said free end is remote from said overflow cup, said combination valve and pivot device be-' ing provided with a passage, a portionof which is located within said fixed member and communicates with the interior of said suction line, another portion of which is located within said movable member and communicates with the interior of said withdrawal tube, said two portions of said channel terminating at said surface of relative motion between said two members, said terminals of said two portions of said channel being adapted to align with each other when said withdrawal tube is in said operative position, whereby a continuous suction passage is provided from said suction line to said withdrawal tube when said withdrawal tube is in said operative position, said terminals of said two portions of said channel being adapted to be out of alignment with each other to form a closed valve between said suction line and said withdrawal tube when said withdrawal tube is in said inoperative position.

7. In combination, a viscometer having a plurality of viscometer tubes, each of said viscometer tubes being provided with an overflow cup surrounding the top of each tube, a main suction line, an off-take suction line for each of said viscometer tubes, a withdrawal tube cooperating with each of said off-take suction lines and adapted to cooperate with one of said overflow cups to withdraw excess liquid therefrom, said excess liquid being withdrawn through said withdrawal tube, said off-take suction lines and said main suction line, and valve means associated with each withdrawal tube.

8. In combination a viscometer having a plurality of viscometer tubes, said viscometer tubes each being provided with an overflow cup surrounding the top of said tube, a main suction line, an off-take suction line for each of said viscometer tubes, a withdrawal tube cooperating with each of said ofl-take suction lines, and means disposed between each of said off-take tubes and the corresponding withdrawal tube for providing relative motion therebetween, each of said withdrawal tubes being adapted to cooperate with one of said overflow cups to withdraw excess liquid therefrom, said excess liquid being with drawn through said withdrawal tube, said ofi take suction line and said main suction line.

9. The combination of claim 8 in which sai means are combination valve and pivot devices ELMER H. PAYNE. 

